Identify suspicious connections and IP addresses

Identify suspicious connections and IP addresses:
- such entries should be highlighted in:
- the network host list in _Overview_ page
- the _Inspect_ page table
- a new notification kind should be added to warn about suspicious connections

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Identification of suspicious IPs via blacklists has already been implemented.
This issue wants to track the need to identify suspicious traffic with more advanced techniques such as deep packet inspection (DPI).